 "Provincial Highway 48" ran between Grovenlock and Willow Creek; however in the 1960s, it was renumbered to Highway 348.In 1971, the "Chesterfield Bridge" across the South Saskatchewan River was opened, extending Highway 21 to Eatonia.Bridges were opened across the Battle and North Saskatchewan Rivers were opened later in the decade, and along with the renumbering Highways 348, 30, and 330, Highway 21 assumed its present length.